Control system and apparatus for air compressors



.M'ay 6 1924. 1,493,261

' w. s. H. HAMILTON CONTROL SYSTEM AND APPARATUS FOR AIR COMPRESSORS Filed Jan. 28 1921 Fig. I,

CONNECTED TO CONNECTED I'O RESERVOIR ON FIRST RESERVOIR 0N TRAIN UNIT SECONDTRAIN UNIT Inventor 2 William S. H. Hamilton,

Patented May 6, 1924.

.SSWSUNIZTED STATES 1,493,261 PATENT mi e..."

7 WILLIAM s. n. HAMILTON, or soHENEcTAnY, NEW YORK, AssiGNon "ro GENERAL ELECTRIC COMPANY, A CORPORATION} on NEW YORK,

ooNTRoLsvsrErr AND APPARATUS non zAIR COMPRESSORS."

Application filed. January 28, 1921., Serial 110.440,?67,

I To all whom it may concern:

Be it known that 1, WILLIAM S. H. HAMIL- 'ToN,a citizen of the United States, residing at Schenectady, county ofSchenectady, State of New. York, have invented certain new .and useful Improvements in Control Systems and Apparatus for Air Compressors,

of which the following is a specification.

My invention relates to the control of 1 electrically driven air compressors, and in particular to the control of air compressors for railway train units.

, Such air compressors are ordinarily operated by means of electric motors energized from the trolley circuit, and the motors are controlled responsively to the reservoir air pressure through a low potential circuit. A motor generator operated from the trolley circuit is usually provided for furnishing the lowpotential for the control circuits. A synchronizing wire is ordinarily provided to interconnect the compressor control equipments on the various train units so that all of the compressors are simultaneously stopped when all of the reservoirs I have been charged to at least the upper pressure limit; or in other words, the last reservoir to be charged to the pressure limit controls all of the compressors. Such equipments have heretofore had the disadvantage that it'was necessary to operate'the motor generators during both single unit and multiple unit operation. It is wasteful of power to operate the motor generator on a 'struction and arrangement-of my invention Wlll'be pointed out particularly hereinafter.

85 train unit at all times, because when the unit is standing idle the power consumed by the -motor generator is practically wasted. It has heretofore been proposed to employ a storage battery to furnish the low potential I 40 control power instead of the motor generator set,but a storage battery is expensive,

it is heavy, it requires considerable maintenance, and it is ineflicient. It has also been proposed to energize the control wiring directly from the trolley circuit, but that is impractical where the trolley voltage is relatively high, as is the case in modern long distance electrifications, because of the fact compressor having an 616011110 motor 110.

that the synchronizing wire is usually in so .cluded in a cable running between the cars along with other control wires, and serious trouble will result if this wire becomes accide'ntally crossed with any of the other control wires.

One of the objects of my invention is to provlde'an improved arrangement, employing a, suitable source o f-;low potential such as a motor generator, in which the control ofthe compressor motor on each train unit is dependent on the. low potential source only for multiple unit synchronous operat1on., In case the. lowpotential source is a motor generator set, it may be shut down when the train unitis standing idle, or in case the motor; generator set 'is disabled while thetrain unit is operating in atrain with other units, the compressor on,that

train unit.may continue to operate to give fairly good results. .p

An0ther object of my invention is the pro vision of anzarrangement in which allthe compressors on the various train units are automatically shut down when any one of the reservoirs has been charged to the predetermined value, regardless of the fact that the, other reservoirs may not beIcharged to as high a pressure. Poweris therefore saved, since to wait until all of the reservoirs are charged to the predetermined pressure may mean that one or more of'the reservoirsmay be charged beyondthe required pressure, and the. air is therefore 1 wasted through the operation of relief valves. The pressure of the various reservoirs will equahze so that noneof themwill be charged beyond the pressure limit, thus saving air and power.

,Certain' advantageous features of con- For a better understanding of my invention, reference is had to the accompanying drawings showing an embodiment of my invention for purposes of illustration, and in which Fig. 1 shows in simplified diagram the air compressor system. on asingle train un1t,- and Fig. 2 shows the manner-in which the train units are'interconnectedby means of a synchronlzing wire 1n; order to carry into effect certainrof the .ob ects of my-mvention. 3

I Referring to Fig. 1, the motor'driven air ,,invention is applicable generally tocom-- rear respectively of the train unit.

pressed air systems, I have illustrated it in connection with a straight air braking equipment for a train unit, and have shown merely enough of the air braking equipment to indicate to those skilled in the art one of the uses of my invention. This air braking sys tem is shown in very simplified diagram, and as shown. comprises an air brake cylinder 13 connected to a brake pipe 14 which is controlled by means-of the two engineers valves 15 and 16 located at the front alt ifid e reservoir 12 is connected to the main reservoir pipe 17. The brake pipe 14 and the main. reservoir pipe 17 are connected to corresponding pipes of the two braking equipments of other train units by means of the couplings shown on the ends of the pipes. Since the compressed air systems on the various train units are substantially duplicates of each other, merely the one equipment has been shown,'and it is to be understood that this equipment is intended to be 'used' either singly or in connection with other train units. The compressor motor sureinthe reservoir 12, by means of a pneumatically operated switch 18, the details of which will be hereinafter described. An

electropneumatic valve 19 is adapted to control the operation of the pneumatic switch 1'8, and this valve is adapted to be either mechanically operated by means of the electropneumatic or governor switch 20 or magnetically in response to the energization of the magnet winding 21 which is connected in the synchronizing wire 22 which interconnects the various train units.

A source of low potential comprising the motor generator set 23 is adapted to supply control power for the synchronous operation of the compressors on the various train units. This motor generator set is controlled bymeans ot' the manually operated switch 1 '24 having one set of contacts 25 which completesthe circuit to themotor of the set,

and another set of contacts 26 which completes the circuit from the. generator of the set to the synchronizing wire 22.

The pneumatically operated switch 18 is provided with contacts 27 which control the energization of the compressor motor 10 from the supply circuit designated by the trolley wire 28. The movable element of the switch contacts 27 is operated by means of a pneumatic device 29 which is controlled by-means of the valve 19. The pneumatic switch mechanism also comprises a man- 'ually operated switch member 30 which is included in the circuit from the generator of 1 the motor generator set to the synchronizing wire 22 and is adapted to control the supply of a low potential'power to the synchroniznizing wire.

energized to close.

ing wire. This switch member is mounted upon a sliding rod 31 suitably supported and held in the closed position by means of the spring-pressed detent 32.

As thus constructed and arranged, the operation of my invention is as follows: With the parts in the various positions shown in the drawings, closing the pilot switch 33 connects the compressor motor 10 to the high potential supply circuit through the contacts 27 of the pneumatically operated switch 18. The compressor 11=will operate 'to supply air under pressure to the reservoir 12, and when the pressure in this reservoir rises to the predetermined value, the pneumatically operated switch governor 20 will mechanically raise the valve 19 so as to admit air from the reservoir 12 tothe cylinder of the pneumatically operated device 29 for the switch 18. The movable member of the pneumatically operated contacts 27 will thereby'be moved against the tension of the spring 34 to the open position, thereby deenergizing the compressor motor 10.

The above described operation will take place irrespective as to whether or not the motor generator 23 is supplying control power for effecting the synchronous operation of the various compressors. Assume that synchronous operation is desired. The manually operated switch-24 will be thrown tothe right so as to close the switch contacts 25 and 26, and assuming that the switch-rod 31 has been manually moved to the position shown in the drawing at which the detent 32 holds this rod in the position so that the contact 30 completes the circuit from the generator to the motor generator set, the electromagnetic switch 35 will thereupon be energized to close its contacts. If'now the pneumatically operated switch 20 is caused to close by reason of the fact thatthe pressure in the reservoir 12 has been built up to the proper value, the magnet winding 21 of the electropneumatic valve 19 will be energized and the synchronizing wire 22 will be grounded throughout. This will cause the valve magnets 21' of the other equipmentsto be energized through the synchro- It is to be understood that I have merely shown diagrammatically the equipment of one train unit for purposes of illustration, but by reference 'to Fig. 2, it will be seen that I contemplate that any desired number will be energized to close from its-low po-- tential source of supply in the samemanner as the switch 35 of'the'first equipment is" It will also bejunderstood that the pneumatic switch 20 Will-be operated responsively to the pressure in the reservoir of the second equipment.

r ea-mi In case any one of the reservoirs on the various train units is first charged to the predetermined value, the pneumatic switch corresponding to the pneumatic switch 20of the equipment shown in Fig. 1 will close and establish a ground connection for the synchronizing wire, thereby energizing the other magnet valve or valves corresponding to the valve 19 of Fig. 1. The other valve or valveswill be magnetically raised and admit air under pressure from their respective reservoirs so as to operate all of the pneumatic switches corresponding to the switch 18 of Fig. 1 and thereby deenergize all of the compressor motors simultaneously. A saving of power is thereby efl'ected, since it is not necessary to wait until all of the reservoirs have been charged to the predetermined pressure. It will be obvious to those skilled in the artthat in certain of its aspects, however, invention is not necessarilydimited to an arrangement in which all of'the' compressors are shut down when one of the reservoirs has first reached a predetermined pressure.

If the equipment shown in Fig. 1 is to be operated as a single unit equipment, the motor generator set 23 may be shut down. This will be efiected by opening the manually operated switch 24 and tripping the detent 32, thereby permitting the switch 30 to open the circuit to the synchronizing wire in accordance with the bias of the spring 34. The electromagnetic switch 35 will thereby be deenergized and open the circuit for the valve magnet 21. The pneumatically operated switch 27 will now be operated directly and solely in accordance with the pressure of the reservoir 12. It will therefore be seen that it will only be necessary to operate the motor generator set when multiple unit synchronous operation of a plurality of compressor equipments on various train units is desired, and that no power need be wasted in the motor generator sets for the control of the compressor equipment in case the train units are operated singly.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. The combination in a compressed air system, of a motor driven compressor for supplying compressed air to the system, a source of low potential for supplying con trol power for controlling the compressor motor, a synchronizing wire energized from the low potential source and adapted to interconnect the control of said compressor with the control of other compressors supplying compressed air to the system, and means whereby the said compressor is adapted to control or be controlled by the other compressors of the system when the source of low potential is supplying control power, and the said compressor is independently controlled responsively to the air pressure set up by said compressor in case'the source of low potential is not supplying control power. h

2. The combination in a'compressed air system, of a motor driven compressor for supplying compressed air to the system, a source of'low potential for supplying control power, for controlling the compressor motor, a synchronizingwire' energized from the low potential source and adapted. to interconnect the control of said compressor with the control of other compressors supplying compressed air to thesystem, a pneumatically operated switch for controlling the" motor'of said compressor, and means whereby the said switch is operated responsively to the air pressure set up by said com prcssor and is controlled through the synchronizingwire.

3. The combination in a compressed air system, of a motor driven-compressor for supplying compressed air to the system, a source of. low potential. for supplying con trol power for controlling the compressor motor, a synchronizing wire adapted to interconnect the control of said compressor with the control of other compressors supplying compressed air to the system, a pneumatically operated switch for controlling the motor of said compressor, avalve controlling said switch, and means whereby the said valve is controlled through the synchronizing wire and is operated responsively to the pressure set up by said compressor.

4. The combination in a compressed air system, of a motor driven compressor for supplying compressed air to the system, a source of low potential for supplying. con trol power for controlling the compressor motor, a synchronizing wire adapted to in terconnect the control of said compressor with the control of other compressors supplying compressed air to the system, a pneumatically operated switch for controlling the motor of said compressor, ,a magnet valve controlled through the synchronizing wire for controlling the said switch, and means whereby the said valve is mechanically operated in response to the pressure set up by said compressor.

5. The combination in a compressed ai system employing a plurality of motor driven compressors, of a separate switch for controlling each compressor motor, a synchronizing wire for interconnecting the con trol of the compressor motor switches, and means whereby all of the switches are substantially simultaneously operated to deenergize all of the compressor motors when the pressure set up by any one of the com pressors first rises ,to a predetermined value.

6. The combination in a compressed air system employing a plurality of motor driven compressors, of a separate pneumatically operated switch for controlling each compressor motor, a synchronizing wire for interconnecting the control of the compressor'motor switches, and means whereby the pneumatic switch associated with each compressor motor is operated to deenergize the motor responsively to the pressure set up by the compressor driven thereby rising to a predetermined value, and the other pneumatic switches are controlled through the synchronizing wire to substantially simultaneously deenergize the respective motors controlled thereby.

7. The combination in a compressed air system employing a plurality of motor driven compressors, of a separate pneumatically operated switch for controlling each compressor motor, a synchronizing wire for interconnecting the control of the compressor motor switches, and means whereby when the pressure set up by any one of the compressors first reaches a predetermined maximum value, the pneumatic switch associated with that compressor opens and the other pneumatic switches are controlled through the synchronizing wire to substantially simultaneously open.

8. The combination in a compressed air system employing a plurality of motor driven compressors, of a separate pneu matically operated switch for controlling each compressor motor, a sy-nchronizingwire for interconnecting the control of the compressor motor switches, a magnet Valve having its winding connected to the synchronizing wire for controlling each pneumatic switch, and means whereby when the pressure set up by any one of the compressors my hand this 27th day of J anuary, 1921.

WILLIAM S. H. HAMILTON. 

